The Analytical core will provide state-of-the-art analyses that are of high priority to CCEH projects that link chemical exposures with clinical and epidemiological data (Project 1), epigenetic data (Project 2), immunological data (Project 3), and mechanistic data from human neurons (Project 4). Analytical Core will use its extensive experience in analytical chemistry to develop and validate highly sensitive and specific methods to quantitate target compounds in small volumes of plasma from mothers and children, in breast milk, and in urine. Specifically, the Analytical Core will serve center projects by conducting analyses on complex biological samples matrices to identify xenobiotic pollutants that are known or suspected of being developmental neurotoxicants and immunotoxicants, in human epidemiological studies and/or in animal models. Quantitative results will be provided to all CCEH Projects where they will be evaluated in the context of ASD risk, genomic and methylomic interactions, cytokine profiles and their ability to alter Ca^'^-dependent signaling pathways in human neurons and immune cells. The Core's three main objectives are: Objective 1: Provide general analytical support for efficient processing and extraction of small sample volumes archived in the CCEH biobank. Objective 2: Undertake highly sensitive and quantitative analytical chemistry techniques to determine concentrations of polybrominated diphenyl ether (PBDE), polychlorinated biphenyl (PCB), and perfluorinated compounds (PFCs) congener patterns present in maternal serum and pyrethroid pesticide metabolites in urine of women at high risk for giving birth to an autistic child participating in the MARBLES study, and those found in children and their mother participating in CHARGE Objective 3: Develop and implement new analytical techniques to measure. This will include the development of: 3.1. PBDE and PCB congener profiles in the same extracts; and 3.2. Hydroxylated PBDE and PCB (OH-PBDE and OH-PCB) metabolites in the same extracts.